Internal combustion engines for marine drives often have an idle air control valve that is configured to regulate the flow of air into an intake manifold of the engine when a throttle plate of the engine is either closed or nearly closed. Some examples of idle air control valves are disclosed in U.S. Pat. Nos. 5,722,367 and 4,337,742. Further examples of idle air control valves are described herein below with reference to FIGS. 1-4.
U.S. Pat. No. 6,647,956, which is hereby incorporated herein by reference in entirety, discloses an idle air intake system for a marine drive having a fibrous pad disposed in an air conduit leading to the idle air control valve. The fibrous pad is configured to decrease noise emanating from the idle air control valve.
Through research and development, the present inventor has determined that it is desirable to provide improved noise attenuating systems for marine engines. It is desirable to provide noise attenuating systems that are more modular in configuration and adaptable to a wide variety of intake system configurations. The present inventor has further determined that inclusion of a fibrous pad, such as disclosed in U.S. Pat. No. 6,647,956, can be unduly restrictive to air flow and thus can adversely affect performance of the engine. The fibrous pad also requires a dedicated mounting structure or some other means for retaining the pad within the air flow conduits. This disadvantageously complicates manufacture and adds cost.
The present inventor recognizes that it would be significantly beneficial if an inexpensive device could be provided for reducing the sound level caused both by the operation of the idle air control valve and the air flowing through the conduit associated with the idle air control system. The present disclosure is a result of the present inventor's efforts to overcome these and other drawbacks found in the prior art.